Process control systems, like those used in chemical, petroleum or other process control plants, typically include one or more process controllers and input/output (I/O) devices communicatively coupled to at least one host or operator workstation and to one or more field devices via analog, digital or combined analog/digital busses. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure and flow rate sensors), perform functions within a process such as opening or closing valves and measuring process parameters. The process controllers receive signals indicative of process measurements made by the field devices and/or other information pertaining to the field devices, use this information to implement a control routine, and then generate control signals that are sent over the busses or other communication lines to the field devices to control the operation of the process. In this manner, the process controllers may execute and coordinate control strategies using the field devices via the busses and/or other communication links communicatively coupling the field devices.
Information from the field devices and the controller is usually made available over a data highway to one or more other hardware devices, such as operator workstations, personal computers, data historians, report generators, centralized databases, etc., typically placed in control rooms or other locations away from the harsher plant environment. These hardware devices run applications that may, for example, enable an operator to perform functions with respect to the process, such as changing settings of the process control routine, modifying the operation of the control modules within the controllers or the field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for the purpose of training personnel or testing the process control software, keeping and updating a configuration database, etc.
As an example, the DeltaV™ control system, sold by Fisher Rosemount Systems, Inc., includes multiple applications stored within and executed by different devices located at diverse places within a process plant. A configuration application, which resides in one or more operator workstations, enables users to create or change process control modules and download these process control modules via a data highway to dedicated distributed controllers. Typically, these control modules are made up of communicatively interconnected function blocks, which are objects in an object oriented programming protocol that perform functions within the control scheme based on inputs thereto and that provide outputs to other function blocks within the control scheme. The configuration application may also allow a configuration designer to create or change operator interfaces which are used by a viewing application to display data to an operator and to enable the operator to change settings, such as set points, within the process control routines. Each dedicated controller and, in some cases, field devices, stores and executes a controller application that runs the control modules assigned and downloaded thereto to implement actual process control functionality. The viewing applications, which may be run on one or more operator workstations, receive data from the controller application via the data highway and display this data to process control system designers, operators, or users using the user interfaces, and may provide any of a number of different views, such as an operator's view, an engineer's view, a technician's view, etc. A data historian application is typically stored in and executed by a data historian device that collects and stores some or all of the data provided across the data highway while a configuration database application may run in a still further computer attached to the data highway to store the current process control routine configuration and data associated therewith. Alternatively, the configuration database may be located in the same workstation as the configuration application.
Configuration applications may include objects from a library of template objects, such as function block template objects and, in some cases, control module template objects. These configuration applications are used to configure a control strategy for a process plant. The template objects have default properties, settings and methods associated therewith and the engineer using the configuration application can select these template objects and essentially place copies of the selected template objects into a configuration screen to develop a control module. During the process of selecting and placing the template objects into the configuration screen, the engineer interconnects the inputs and outputs of these objects and changes their parameters, names, tags and other properties to create process control objects that are interconnected and included in a specific control module for a specific use in the process plant. After creating one or more such control modules, the engineer can then instantiate the control module and download it to the appropriate controller or controllers and field devices for execution during operation of the process plant.
Thereafter, the engineer generally creates one or more displays for operators, maintenance personnel, etc. within the process plant by selecting and building display objects in a display creation application. These displays are typically implemented on a system wide basis in one or more of the workstations and provide preconfigured displays to the operator or maintenance persons regarding the operating state of the control system or the devices within the plant. Typically, these displays take the form of alarming displays that receive and display alarms generated by controllers or devices within the process plant, control displays indicating the operating state of the controllers and other devices within the process plant, maintenance displays indicating the functioning state of the devices within the process plant, etc. These displays are generally preconfigured to display, in known manners, information or data received from the process control modules or the devices within the process plant. In some known systems, displays are created through the use of process control objects that have a graphic associated with a physical or logical element and that is communicatively tied to the physical or logical element to receive data about the physical or logical element. The object may change the graphic on the display screen based on the received data to illustrate, for example, that a tank is half full, to illustrate the flow measured by a flow sensor, etc.
Similar to the control configuration application, a display creation application has template graphical display items, such as tanks, valves, sensors, operator control buttons like slide bars, on/off switches, etc. which may be placed on a screen in any desired configuration to create an operator display, maintenance display and the like. When placed onto the screen, individual graphic items may be interconnected on the screen in a manner that provides some information or display of the inner-workings of the process plant to different users. Each individual graphic item may be associated with an object and/or a class of objects.
In a process control plant using a process control system, operators and/or other process control plant personnel often need to communicate information regarding a particular control loop, function block, device or other physical or logical process control element to safely, efficiently and profitably operate the process control plant. Communication may need to occur, for example, between plant personnel located in different parts of the plant or working different shifts. This information may be manually delivered through hand-written notes in a paper logbook or via physical sticky notes placed on an operator console. Manual message delivery methods, while quick and convenient, may often result in the operator communications being overlooked, lost, not easily located or not easily referenced or distributed to necessary parties.
Alternatively, communication of information between operators may occur via electronic logbooks, email, or other electronic media or methods. Compared to manual methods, electronic methods of communication of information between operators or plant personnel may be more permanent and not as easily lost, however, electronic methods may provide different types of inconveniences. For example, in order to send an email including contents from both an electronic logbook entry and an associated section in an device specification manual with regard to a faulty device, an operator may need to run applications that are not co-resident on or co-accessible from the operator's control console. The operator is forced to determine which application must be run and where the application or associated data is located, thus taking the operator's time, attention, and in some cases even physical presence away from the operator's primary tasks at hand. Moreover, the scope and timing of electronic communication distribution is still largely dependent on each individual message sender. The incongruence of determining contents and recipients as well as searching for, accessing, and distributing messages, applications and data may result not only in operator inconvenience, but also may result in a potentially dangerous situation, for example, if the operator is distracted away from the operator's plant operation responsibilities.